Comparing Different Output Metrics of High-Resolution MEMS Weakly Coupled Resonant Tilt Sensors

This article presents the theoretical analysis and experimental investigation of a weakly coupled resonant tilt sensor based on different output metrics, including mode frequency, amplitude ratio (AR), amplitude difference, and eigenstate. Especially, we investigate the sensitivity, linear working range, stability, and noise analysis by theoretical analysis and evaluation of experimental results. The tilt sensor sensing element is the weakly coupled resonators, the output metrics of which shift are proportional to the effective stiffness perturbation caused by changes in input inertial force along the sensitive axis when any tilt angular is applied to the tilt sensor. Furthermore, it is demonstrated that there is an optimal operating point for amplitude difference output through theoretical analysis. The experimental results show that the minimum input-referred angle noise densities of the tilt sensor based on the AR and amplitude difference are 1.03 x 10(-4) and 9.10 x 10(-5)degrees./v Hz, respectively. In addition, the weakly coupled resonant tilt sensor based on the AR and amplitude difference outputs achieve resolutions of 9.79 x 10(-5)degrees and 7.53 x 10(-5)degrees with an integral time of 15 s, and the mode frequency output achieves a resolution of 0.141 x 10(-5)degrees with an integral time of 0.5 s. The experimental results demonstrate that based on amplitude difference output has the best long-term stability and based on the mode frequency output has better short-term stability. Additionally, it is demonstrated that the output based on the AR balances sensitivity, linear range, and long-term stability.

Automated summary

This article presents a theoretical and experimental study of a weakly coupled resonant tilt sensor based on different output metrics. The sensor's sensitivity, linear range, stability, and noise analysis are investigated. Experimental results show that the sensor achieves high resolutions and the output based on amplitude difference has the best long-term stability, while the output based on mode frequency has better short-term stability. The output based on amplitude ratio balances sensitivity, linear range, and long-term stability.